ncsp mcnp 2017 · MCNP Progress for NCSP LA-UR-17-21840 2 Abstract MCNP Progress for NCSP Forrest Brown, Michael Rising, Jennifer Alwin Monte Carlo Methods, Codes, & Applications,

MCNP Progress for NCSP LA-UR-17-21840 27

LA-UR-17-21840 Approved for public release; distribution is unlimited.

Title: MCNP Progress for NCSP

Author(s): Brown, Forrest Rising, Michael Alwin, Jennifer

Intended for: DOE-NNSA-NCSP Technical Program Review Washington, DC, 2017-03-14

Disclaimer: Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by the Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under contract DE-AC52-06NA25396. By approving this article, the publisher recognizes that the U.S. Government retains nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or to allow others to do so, for U.S. Government purposes. Los Alamos National Laboratory requests that the publisher identify this article as work performed under the auspices of the U.S. Department of Energy. Los Alamos National Laboratory strongly supports academic freedom and a researcher's right to publish; as an institution, however, the Laboratory does not endorse the viewpoint of a publication or guarantee its technical correctness.

LA-UR-14-27037Approved for public release; distribution is unlimited.

Title: New Hash-based Energy Lookup Algorithm for Monte Carlo Codes

Author(s): Brown, Forrest B.

Intended for: OECD-NEA-WPNCS Expert Group Meeting - Advanced Monte Carlo Techniques,2014-09-15/2014-09-19 (Paris, France)MCNP documentation

Issued: 2014-09-08

LA-UR-14-27037Approved for public release; distribution is unlimited.

Title: New Hash-based Energy Lookup Algorithm for Monte Carlo Codes

Author(s): Brown, Forrest B.

Intended for: OECD-NEA-WPNCS Expert Group Meeting - Advanced Monte Carlo Techniques,2014-09-15/2014-09-19 (Paris, France)MCNP documentation

Issued: 2014-09-08


MCNP Progress for NCSP

Forrest Brown, Michael Rising, Jennifer Alwin Monte Carlo Methods, Codes, & Applications (XCP-3) X Computational Physics Division

LA-UR-17-21840


Abstract

MCNP Progress for NCSP

Forrest Brown, Michael Rising, Jennifer Alwin Monte Carlo Methods, Codes, & Applications, LANL

The DOE-NNSA Nuclear Criticality Safety Program (NCSP) supports research, development, maintenance, verification and validation, user support, and training for the MCNP Monte Carlo code for nuclear criticality safety (NCS) customers within DOE-NNSA.

The MCNP Monte Carlo code has been used for high-fidelity analyses of criticality safety problems since the 1970s. This talk summarizes MCNP progress during FY 2016 and early FY 2017. Activities and accomplishments are summarized in five major areas:

–  MCNP6 & Whisper status –  Verification and validation testing –  User support & training –  Work in progress

Work supported by: US DOE-NNSA Nuclear Criticality Safety Program LANL Nuclear Criticality Safety Division LANL PF4 Restart


MCNP Progress for NCSP US DOE-NNSA Nuclear Criticality Safety Program –

What have we done for you lately (FY 2016, FY 2017) ?

– Overview of LANL Analytical Methods Work for NCSP

– MCNP6 & Whisper Status – Verification / Validation – User Support & Training

– Work in Progress •  Whisper – Validation & USLs •  Automated Convergence Diagnostic •  MCNP 2020 – Modernization & Parallel •  Solution Chemistry Effects on Criticality •  Temperature Dependence •  Correlated Fission Multiplicity


Overview of LANL Analytical Methods Work for NCSP

Some activities are partially funded by other programs

All – Ongoing Work MCNP – release & NCS testing MCNP – maintenance & bug-fixes MCNP – benchmark catalogs Training – MCNP criticality classes Training – NCS validation, SU methods Verification-validation Criticality documentation Best Practices for Criticality Calcs MCNP Reference Collection MCNP Forum email users group MCNP web site User support

Jennifer Alwin Criticality & NCS validation MCNP – Whisper vs ANS-8.24 MCNP – solution chemistry PF4-NCS support & training Collaboration – SNL

Forrest Brown Whisper support MCNP – physics, algorithms MCNP – MCNP 2020, parallel Teaching – Professor at UNM Collab – SNL, UNM, RPI, Mich, MIT

Michael Rising Fission neutron multiplicity MCNP – physics, code MCNP – MCNP 2020 Summer intern – Oregon St Collaboration – SNL, UNM

In-depth experience & expertise in all areas: theory, codes, computers, applications, user support, teaching, design, validation, …..


MCNP6 & Whisper Status


MCNP6 & Whisper Status (1)

•  MCNP releases by RSICC

MCNP6.1 – 2013, production version MCNP6.1.1 – 2014, same criticality, faster, beta features for DHS MCNP6.2 – 2017, with Whisper code & benchmarks

Nuclear Data – ENDF/B-VII.1 data, updates, & older data Reference Collection – 700+ technical reports V&V Test Collection – 1500+ test problems

Supported on Mac, Linux, Windows Used for ~1,000,000 processor-hours / month at LANL

Frequent V&V testing for NCS applications

•  Release status –  In final stages of release testing & User Manual revisions

~ 8,000 code files, ~ 6,000 test files, ~750 documents –  Extensive release-testing by MCNP Team in progress –  Friendly-user testing at LANL & Sandia NCS –  Expected release to RSICC: April or May 2017



mcnp6 Partisn structured mesh,

Abaqus unstructured mesh, linkage to other codes

New Criticality Features Sensitivity/Uncertainty Analysis

Fission Matrix OTF Doppler Broadening

Performance Improvements MPI & Threading Improvements

Fission Neutron Multiplicity New Analytic Benchmarks

Extended ICSBEP V&V Suites Whisper Package, USLs

Continuous Testing ~10 k problems/day

protons, proton radiography,high energy physics models,magnetic fields, heavy ions,

33 other particles, delayed n γ

mcnp5Neutrons, Photons, ElectronsCross-section library physics

Criticality FeaturesShielding, Dose

V&V History, Documentation

cosmic ray background, single-event electron physics,

delayed particle sources,light ions, coincidence tallies, CINDER depletion, activation,

intrinsic sources,detector analysis utilities

~ 2 developers ~ 8-10 developers



P - 08 - 10!

Example Sensitivity Coefficient Profile!

Cu-63: !Elastic Scattering Sensitivity!! !Copper-Reflected Zeus experiment:!

P - 08 - 13!


•  Pu-239: !fission chi(E) sensitivity!! !OECD/NEA UACSA Benchmark Phase III.1!

-0.05

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keff

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sitiv

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Leth

argy

Neutron Energy (MeV)

TSUNAMI-3DMCNP6

Figure 3: Comparison of constrained 239Pu fission-� sensitivities for OECD/NEA UACSABenchmark Phase III.1

47

P - 08 - 12!


H-1: !elastic scattering cross-section sensitivity!! !OECD/NEA UACSA Benchmark Phase III.1!

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0

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1e-10 1e-08 1e-06 0.0001 0.01 1

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TSUNAMI-3DMCNP6MONK

Figure 2: Comparison of 1H elastic scattering cross-section sensitivities for OECD/NEAUACSA Benchmark Phase III.1

46

P - 08 - 11!


U-238: !total cross-section sensitivity!! !OECD/NEA UACSA Benchmark Phase III.1!

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TSUNAMI-3DMCNP6MONK

Figure 1: Comparison of 238U total cross-section sensitivities for OECD/NEA UACSABenchmark Phase III.1

45

ACE Cross-section

Data

Application

MCNP6 Monte Carlo

Criticality Calculation

Application Sensitivity Profile

Whisper Pattern matching –

application sensitivity profile vs catalog

Select similar experiments Statistical analysis to

determine bias & uncertainty & MOS

P - 08 - 10!



P - 08 - 13!



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P - 08 - 11!



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P - 08 - 10!



P - 08 - 13!



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P - 08 - 11!



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P - 08 - 10!



P - 08 - 13!



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P - 08 - 12!



-0.05

0

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P - 08 - 11!



-0.06

-0.05

-0.04

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P - 08 - 10!



P - 08 - 13!



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P - 08 - 12!



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P - 08 - 11!



-0.06

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P - 08 - 10!



P - 08 - 13!



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P - 08 - 12!



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P - 08 - 11!



-0.06

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TSUNAMI-3DMCNP6MONK


45

Catalog of sensitivity profiles for 1100+

experiments

SU-based Analysis

USL Upper Subcritical Limit

for NCS analysis

ACE Cross-section

Covariance Data



•  MCNP6.2 new features –  Same speed as MCNP6.1.1, about 2x faster than MCNP6.1 –  Longer input lines, up to 128 characters –  Warning message regarding bias if using < 10,000 neutrons/cycle –  Analytic criticality benchmarks now use continuous-energy physics –  MCNPtools, ISC – next slide –  Bug fixes

•  Coincident surfaces for rotated universe/fill (25 year old bug) •  Rare S(α,β) sampling error (due to roundoff) •  ACE Data – hydrogen (n,γ), SiO2 S(α,β)•  300+ bug-fixes since MCNP6.1, non-criticality

•  Whisper-1.1 –  Coding, benchmarks, scripts, & 50+ documents –  Benchmark catalog - 1101 ICSBEP problems –  Portable to Mac, Linux, Windows


MCNP Utilities

•  Recent upgrades –  mcnp_pstudy.pl - additional options to work with Whisper –  simple_ace.pl - one-speed continuous energy cross sections

•  New tools released (with MCNP6.2) –  ISC - Intrinsic Source Constructor Library

•  Used to generate radiation sources for transport code input (SDEF) •  Written in C++ with Python bindings

–  MCNPTools •  Library that provides object-oriented access to MCNP outputs

–  MCTAL files –  MESHTAL B (MCNP5/FMESH) files –  PTRAC files

•  Written in C++ with Python and Perl bindings •  Other features also included

•  Coming soon (not with MCNP6.2) –  DRiFT - Detector Response Function Toolkit


Verification &

Validation


MCNP Verification & Validation (1)

Verification Suites

•  REGRESSION–  Run by developers for QA checking

•  VERIFICATION_KEFF–  Analytic benchmarks, exact solutions for keff –  Continuous-energy & multigroup

•  VERIFICATION_GENTIME–  10 benchmarks for reactor kinetics parameters

•  KOBAYASHI–  6 void & duct streaming problems, with point

detectors, exact solutions

•  Ganapol Benchmarks–  Exact, semi-analytic benchmark problems–  Fixed source, not criticality

•  Gonzales Benchmark–  Exact analytic benchmark with elastic scatter,

including free-gas scatter

Validation Suites

•  VALIDATION_CRITICALITY –  31 ICSBEP Cases, too small for serious V&V –  Today, used for

•  Code-to-code verification, with real NCS problems & data

•  Compiler-to-compiler verification, with real NCS problems & data

•  Timing tests for optimizing MCNP coding & threading

–  Run at least weekly, to check MCNP6 for NCS

•  VALIDATION_CRIT_EXPANDED –  119 ICSBEP Cases –  Broad-range validation, for developers

•  VALIDATION_CRIT_WHISPER –  1101 ICSBEP Cases –  Used with Whisper methodology for serious

validation –  Will be expanded, as time permits

•  Sandia benchmarks •  Others


MCNP Verification & Validation (2)

•  How accurate is MCNP6 if cross-sections & dimensions are exact?

–  Verification_Keff analytic suite with continuous-energy, 0-D & 1-D –  37 problems run using continuous-energy, 250 M neutrons each –  Results match exact analytic solutions within 0.00003 +- 0.00003

•  Free-gas scattering benchmark (Gonzales) –  Analytic benchmark for slowing down in an infinite medium, with

elastic scattering – including free-gas scattering –  MCNP

•  Constant cross-sections, with Doppler broadened scattering

•  Elastic scatter with target mass A & temperature T

•  Continuous-energy elastic scatter, including target motion


User Support &

Training


User Support

•  User support –  MCNP Forum - User-group, beginners & experts, ~ 1500 members –  MCNP Website –  MCNP Reference Collection, > 700 technical reports –  Summer students (UNM, MIT, Michigan, RPI, Oregon St) –  Direct hands-on support for LANL NCS Division –  Email consulting to many crit-safety analysts

•  University classes –  Monte Carlo class for seniors & grad students at

University of New Mexico, Nuclear Eng. Dept. –  Monte Carlo lectures for XCP Computational Physics Workshop

•  Conferences & Journals –  Nuc Sci Eng, Annals of Nuc En, Prog Nuc En, others –  M&C-2015, ICNC-2015, PHYSOR-2016, M&C-2017 –  ANS …, Anaheim, San Antonio, Washington, Las Vegas, … –  OECD Expert Groups - Advanced Monte Carlo, Sensitivity-Uncertainty


MCNP & Whisper Training

•  MCNP Classes –  Theory & Practice of Criticality Calculations with MCNP (4 days)

•  16 theory lectures (537 slides), 18 practical lectures (780 slides), 190 examples, greatly expanded coverage of SU-methods (Whisper)

•  FY15: 3 classes (2 LANL, 1 Y-12) •  FY16: 3 classes (2 LANL, 1 Sandia) •  FY17: ? classes (2 LANL, ???)

•  Whisper & SU-methods Training –  ½-day MCNP-Whisper training module for NCS analysts

•  Presented 2 LANL, 1 Sandia, 1 IRSN –  2-day Sensitivity-Uncertainty & MCNP-Whisper Training

•  Presented at 2016 EFCOG-NFS workshop •  MCNP-Whisper vs traditional approaches

–  Detailed lecture notes on validation, SU methods, Whisper •  Informal talks at LANL, ~25 hrs, 262 slides

•  Training available for any DOE site crit-safety group, just ask


Work in Progress

Whisper – Validation & USLs Automated Convergence Diagnostic

MCNP 2020 – Modernization & Parallel Solution Chemistry Effects on Criticality

Temperature Dependence Correlated Fission Multiplicity

Other R&D Work, with Universities


Whisper - Next Steps

•  White paper on Whisper & ANS-8.24 •  Expand the Whisper benchmark suite

–  Ongoing collaboration with Sandia (J Miller, S Henderson) –  Sandia NCS has been using an early-release of Whisper during 2016 –  Exchanged benchmarks (1101 LANL, 866 Sandia) –  Add Sandia benchmarks to Whisper catalog, ~500 new

•  Investigate the impact on benchmark selection & USLs of: –  MCNP6 statistics (noise in SU profiles) –  Different benchmark catalogs (eg, LANL vs SNL) –  Size & completeness of benchmark catalogs –  Analyst or site bias? (no evidence so far)

•  Improved covariance data –  New data from Scale-6.2 –  New data from LANL, using NJOY –  Investigate impact on benchmark selection & USLs


Automatic Convergence Diagnostic •  History

–  MC criticality calculations are iterative –  Fission neutron source distribution must

be converged before computing k-effective & reaction rates

–  For the first 50 years of MC criticality, no tools available to check convergence

–  15 years ago, Ueki & Brown introduced Shannon Entropy of the fission distribution to check convergence

–  Has dramatically improved the quality & correctness of MC criticality, & now used in most MC codes worldwide

•  Today –  Can now diagnose convergence, but

analysts are sometimes “too busy”, or have not been properly educated

–  Need an automated process – code determines convergence

•  Fission matrix –  Discretized Green’s function, region-to-

region probabilities for next-gen fission –  With fine-enough mesh for the F matrix,

eigenfunction is the correct converged fission distribution

•  Fission matrix –  New sparse storage techniques for

MCNP permit the use of very fine meshing for F, hence more accurate

–  Can determine F even if not converged –  Can use F eigenfunction to accelerate

convergence of neutron distribution –  Can use the F eigenfunction to

automatically diagnose convergence, without requiring user action

–  R&D was advanced & demo’d, but completion delayed by the importance of supporting Whisper S-U methods

standard MC

standard MC

keff

Hsrc

accelerated using F matrix

accelerated using F matrix


MCNP 2020 – Status

MCNP 2020 •  Improve performance

–  Goal: 2X speedup within 2 years

•  Upgrade core MCNP6 software –  Evolution, not revolution –  Restructure, clean up code & data

structures, standards compliance –  Reduce future costs for development

& maintenance –  Goal: sustainable code

•  Prepare for future –  New computers – massive parallel,

but less memory per core –  Improve MPI & thread parallelism –  Goal: flexible, adaptable code

MCNP 2020 - Progress: –  2 X speedup over original MCNP6

–  500 k lines of code are now 100% compliant with Fortran-2003 standard

–  Test MCNP6 on Intel Phi (MIC) •  No changes needed in source coding •  Works with 100s of threads •  Needs some tuning

–  Code infrastructure •  Transitioned to GIT for version control •  Consolidated I/O files •  Memory allocation in progress

–  Parallel threading •  Enhancements in progress

–  New compilers •  Intel-15, Intel-16, Intel-17 •  gfortran-5.3, gfortran-6.2


MCNP 2020 - Performance Improvements

Run Times for VALIDATION_CRITICALITY Suite on Various Computers Computer CPU Mem. Processors, MCNP MCNP Total

Speed Speed Cores, Threads Version Time (GHz) (GHz) Hyperthreads used (minutes)

MacBook 2010 2.7 1.1 1 - i7, 2 x 2 HT 4 mcnp6.1.1 88 MacBook 2013 3.0 1.6 1 - i7, 2 x 2 HT 4 mcnp6.1 62

4 mcnp6.1.1 42 Mac Pro 2010 3.0 0.67 2 - Xeon, 4 8 mcnp6.1 44 8 mcnp6.1.1 28 Windows 2012 2.7 1.3 2 - Xeon, 6 10 mcnp6.1.1 19 Mac Pro 2012 2.4 1.07 2 - Xeon, 4 x 2 HT 16 mcnp6.1.1 22

Mac Pro 2014 2.7 1.6 1 - Xeon, 12 x 2 HT 12 mcnp5-1.60 14 12 mcnp6.1.1 14 12 mcnp6.2 12

HP Linux 2015 2.6 2.1 2 - Xeon, 8 16 mcnp6.2 10 HP Linux 2016 3.1 2.4 2 - Xeon, 12 x 2 HT 24 mcnp6.2 8 HP Linux 2017 2.1 2.4 2 - Xeon, 18 x 2 HT 36 mcnp6.2 6½

MCNP6.2 preserves all performance improvements from MCNP6.1.1, and is much faster than MCNP6.1 & slightly faster than MCNP5

Runtimes are wall-clock for the entire suite of 31 problems, including cross-section I/O & output


Solution Chemistry Effects on Criticality

•  Investigating Impact of Chemistry in Modeling Plutonium Solution –  Oxidation state

•  Pu(III), Pu(IV), Pu(V), Pu(VI), Pu(VII) exist in solution •  Pu(III), Pu(IV), Pu(V) and Pu(VI) can exist simultaneously in acid

–  Speciation/Coordination Chemistry •  In Pu(IV) nitrate solutions

–  Pu(NO3)22+ highest concentration in 2 M nitric acid –  Pu(NO3)4 and Pu(NO3)62- in 7 M nitric acid –  Pu(NO3)62- highest concentration in 13 M nitric acid

–  Density –  Effects of Temperature

•  Influences disproportionation and density –  Effects of Radiolysis

•  Influences disproportionation –  Whisper methodology to characterize neutronics

•  Used to compare neutronics of solution system with different ligands •  Investigations comparing plutonium chloride solutions with nitrate solutions

Pu(NO3)62- Los Alamos Science Number 26. 2000.


Temperature Dependence

•  Nearly all NCS calculations are done at room temperature

•  For hot or cold calculations: –  Material densities & problem

dimensions are affected by temperature

–  Neutron physics is affected by temperature: •  Doppler broadening of resonance

cross-sections •  Changes in thermal scattering due

to temperature effect on nuclide motion

•  Changes in epithermal scattering due to temperature effect on nuclide motion

–  In principle, can use NJOY & MCNP with different temperatures, but can be very tedious & error-prone

•  Over the past years, R&D was completed with 4 PhD students on new methods for continuous variation in temperature in MCNP calculations –  On-the-fly Doppler broadening

•  Gokhan Yesilyurt (Michigan) thesis •  Already in MCNP6

–  On-the-fly S(a,b) temperature •  Andrew Pavlou (RPI) thesis •  Demo’d in MCNP6

–  On-the-fly unresolved resonances •  Jonathan Walsh (MIT) thesis •  Demo’d in OpenMC code

–  DBRC •  Doppler broadening resonance

correction for epithermal scatter •  Eva Sunny (Michigan) thesis •  Demo’d in MCNP5

•  These can all be made permanent features in MCNP6


Secondary Emission from Fission

•  Fixed-source nuclear nonproliferation and safeguards needs (NA-22)

•  Neutron and Gamma-ray emission from fission fragments

•  Multiplicity distribution of neutrons and gamma rays

•  Multiplicity-dependent energy spectra •  Angular

emission from fission fragments

Correlated Fission Multiplicity

What’s New in MCNP6.2

•  CGMF based on Monte Carlo Hauser-Feshbach theory (LANL)

•  FREYA based on Monte Carlo Weisskopf theory (LBNL/LLNL)

•  Not available for criticality calculations yet… (UNM student thesis work)

0 2 4 6 8 100

5

10

15

20

Neutron Multiplicity

Photon Multiplicity

0e+00

1e-02

2e-02

3e-02

4e-02

5e-02

6e-02

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 1 2 3 4 5 6 7 8 9 10

n(thermal)+235U

Prob

abili

ty D

ensit

y, P

(νn)

Neutron Multiplicity, νn

CGMF onlyCGMF-MCNP

FREYA onlyFREYA-MCNP

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

n(thermal)+235U

Prob

abili

ty D

ensit

y, P

(νγ)

Photon Multiplicity, νγ

CGMF onlyCGMF-MCNP


1.5e-02

2.0e-02

2.5e-02

3.0e-02

3.5e-02

4.0e-02

4.5e-02

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

n(1.0273 MeV)+239Pu

Neutron-Neutron Angle (cos(θ))

CGMF onlyCGMF-MCNP



Summary

•  MCNP releases –  MCNP5 is no longer supported, cannot use continuous S(a,b) –  MCNP6.1, MCNP6.1.1, & ENDF/B-VII.1 released in 2013 & 2014 –  MCNP6.2 & Whisper release – April/May 2017

•  All basic KCODE criticality features same as for MCNP5 & MCNP6.1 •  MCNP6 speed improved by 1.2 – 4 X for crit-safety. •  Thorough testing with NCS criticality suites

•  Sensitivity-uncertainty methods –  Whisper methods for validation & USLs are important to LANL & other DOE sites –  Being used routinely in many areas –  Training is available –  Outstanding success due to long-range vision & support from NCSP

•  Ongoing – user support, code maintenance, training •  Work in progress – 6 major areas

–  Whisper, S-U methods –  Automated convergence diagnostic –  MCNP 2020 modernization & parallel improvements –  Solution chemistry effects –  Temperature effects –  Correlated fission multiplicity


Questions ?

Documents

ncsp mcnp 2017 · MCNP Progress for NCSP LA-UR-17-21840 2 Abstract MCNP Progress for NCSP Forrest Brown, Michael Rising, Jennifer Alwin Monte Carlo Methods, Codes, & Applications,